Electric oven



Jan. 12, 1932. J. 1;. SHROYER 1,841,158

ELECTRIC OVEN Filed April 19, 1927 2 Sheets-Sheet 1 Fig. l.

nventoh: i: d acob I... Shrogen J. L. SHROYER 'Jan. 12,1932.

Filed April 19 1927 m. w 5 2 n a w 5 0. 9? o 7 5 o o Q o 1 3 E w M m w w 2 n B km 0 w e 7 w/ W m w 1 \o O O O m Inventor: 010 I... $hr-ogen y Hi 7 1ttorneg dac Patented Jan. 12, 1932 UNITED STATES PATENT OFFICE J'ACOB L. SHROYER, OF OAK PARK, ILLINOIS, ASSIGNOR TO EDISON ELECTRIC AP- PLIANCE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF NEW YORK ELECTRIC OVEN Application filed A ril 19,

' My invention relates to electric ovens and has for its object the provision of a slmple, reliable and eflicient device of this character.

More particularly my invention relates to large electric bake ovens, such as used in restaurants and bakeries, although it obviously has application to various other types of ovens. I

For a more complete understanding of my invention reference should be had to theaccompanying drawings in which Fig. 1 1s a perspective view of an electric oven embodying my invention; Fig. 2 is a side elevatlon view partly in section of the device shown in Fig. 1; Fig. 3 is a front elevation view partly in section of the device shown in Figs. land 2; Fig. 1 is a fragmentary view showing the framework for supporting the inner linings; Fig. 5 is a fragmentary sectional view showing the arrangement of the light for the interior of the oven, while Fig. 6 is an enlarged fragmentary sectional view showing a supporting means for'the switch box.

Referring to the drawings, I have shown my invention in one form in connection with amultiple compartment oven, two baking compartments provided withdoors 10 and 11 being shown. These two compartments are identical in construction, and it should be understood that my invention is applicable to single compartment ovens as well as to multiple compartment ovens. The oven comprises an outer metallic casing or lining 12 and an inner lining 13 which is spaced from the outer casing, the space between thembeing filled with a suitable heat insulating material 14, such as rock wool. The inner lining 13 is a complete metallic receptacle in itself. As usual it has a rectangular cross section and may have a somewhat greater dimension in length than in breadth. At the front end of the lining 13, the top and bottom walls converge to formdownwardly and upwardly inclined portions 15 and 16 re spectively, leading to a throat 17 through which access is had to the interior of the oven. The outer end of this throat is securely joined to the outer casing, for exam- 1927. Serial No. 185,027.

ple by riveting and welding or bolting. As

shown the metal at the end of the throat is bent upward at the top and downward at the bottom to form top and bottom flanges which are secured to the outer casing by rivets 18 to give mechanical strength and by welding 20 is mounted in the top of the oven in the space formed behind the inclined wall15 while at the bottom of the oven a heating unit 21 and a tile deck 22 are secured in the space behind the inclined wall 16. The upper surface of the tile deck is flush with a guard or shelf member 23 secured-in the lower end of the throat so that articles can be easily pushed through the oven opening onto the deck.

The door 10 is hinged at the bottom and'is provided with suitable locking means comprising horizontal bars 24 and 25 which are moved longitudinally to latch and unlatch the oven by turning a central lever 26.v

lVith this construction, it will be observed that the inner lining is continuous through the throat to the outer lining. This eliminates the use of plugs which would be necessary to close up the space above and'below the door if the inner lining were brought out straight. The inner lining is made steamt-ight by welding all joints so that leakage of steam into the heat insulating material is prevented. This construction aflords a tight front for the oven which is thoroughly heat insulated so that loss of heat is prevented. The inner lining is constructed of pieces of sheet metal of the required size which are joined together at the corners of the lining by forming flanges along the edge of one sheet and bending the edge of the adjoining sheet around thisflange. This is shown in Figs. 2 and 3. Joints 27 and 28 (Fig. 2) are formed between the rear wall of the lining and the top and bottom walls. As shownthe top and bottom walls are bent upwardly and downwardly respectively, while the top and bottom edges of the rear wall are bent over and then downward and upward respectively around and behind these flanges. Similar joints 29 and 30 (F ig.'3) are provided between the side walls and the top and bottom walls. It will be observed that these joints act as stiffening means for the inner lining since they form in effect I-beams at the corners. In addition to these seamed joints the corners are also welded to make the inner lining steam-tight. Angle irons 31 are welded to the exterior of the inner lining at the top so as to further stiffen it and prevent sagging from the weight of the insulating material 14.

The connection between the throat 17 and the outer casing forms a support for the inner lining at the front end. At the back end an iron supporting framework 32 is provided. As shown in Fig. 4. this framework is made up from angle irons. The supporting framework for the two inner linings comprises three horizontal angle irons 33, 34 and 35 extending crosswise of the linings. These cross pieces each have a slot 36 in each end, the sides of which embrace the flanges of vertical angle irons 32a secured to the outer casing and acting as guides for the cross pieces. The cross pieces are supported on angle irons 37 and 37a extending vertically on opposite sides of the inner linings. As shown in Fig. 2, the top inner lining is located between the cross pieces 33 and 3a while the lower inner lining is located between the cross pieces 34 and 35. It will be noted that the top and side angle irons engage the inner lining with edge contactonly, the bottom angle irons, however, being placed flatwise to form larger bearing surfaces. This arrangement provides for the smallest possible area of contact between the inner lining and the supporting framework whereby the conduction of heat from the inner lining is made as small as possible. The supporting framework is clamped downward against the bottom of the outer casing by upright bolts 38 and 39 which extend through holes provided in short angle irons 40 and 41 secured to the ends of the upper cross bar 33.

\Vhile any suitable heating unit may be used, I preferably use a unit comprising a metallic framework 42 (Fig. 1) provided with insulating cross bars 43 on which a heating resistor is mounted. The framework is provided at each side with a supporting flange 44. At the top these flanges rest on rails 45 and 4-.6 (Figs. 2 and at opposite sides of the heating chamber and extend substantially the full length thereof from the front to the back. The rails, which are formed of angle irons are each provided with a pivot pin 47 at the back whereby the front ends of the rails may be dropped down to permit the heating unit to he slid bodily into or out through the door opening. The front ends of the rails are secured in raised positions by pins 48 extending through suitable apertures in the rails and preferably provided with a cotter pin (not shown) at the end to prevent the rail from slipping off. The rails lit the pivot pins 47 so loosely that they may be moved sidewise somewhat off the pins 48 at the front and thereafter lowered when it is desired to remove the heating unit.

The heating unit- 21 in the bottom of the oven is similar in construction to the upper unit 20 and is supported in a similar manner on rails at opposite sides of the heating chamber, only one of which, 49, (Fig. 3) is shown. These rails are rigidly fixed to the inner lining. The tile deck 22 rests on the rails on top of the supporting flanges for the lower heating unit 21. In removing the lower heating unit the tile deck is first slipped out and then the heating unit may be removed. The tile deck comprises a metallic framework 50 in which the heat refractory tile bricks 51 are permanently secured. The entire deck is thus movable as a unit.

Each oven chamber is provided with an electric lamp at the front at the upper right hand side, the construction of which is shown in detail in'Fig. 5. The inner lining 13 is provided with an aperture surrounded by an extruded cylindrical portion 53 in which threads are formed. A corresponding 0pening is formed in the outer casing 12 and a cylindrical member 54 is inserted between the inner lining and the casing around which the heat insulating material 14 is packed. An electric lamp 55 is mounted on a base 56. The lamp is inserted into the cylindrical member 54L from the exterior of the oven and the base is provided with an internal flange 57 fitting into the member 5% whereby the lamp is secured in central position. The base member is suitably secured to the outer casing. A glass guard 58 is provided around the inner end of the lamp 55. The lamp projects into the heating chamber somewhat and the guard 58 is semispherical in form so as to fitover this projecting portion. The edge of the guard is provided with screw threads which fit into the threads in the portion 53. At the lower end of the portion 53 is a flange 59 against which the guard 58 is screwed tightly, a suitable gasket being provided to assure a steam-tight joint. A reflector 60 is secured to the inner lining on the side of the lamp adjacent the front of the oven so as to reflect the light toward the rear. Ventilating openings 61 are provided in the lamp support 56. A twin conductor 62 leads from the lamp socket through one of the openings 61 to the exterior of the oven where it is provided with a contact plug 63 (Fig. 1) adapted to engage with a plug contact receptacle in the switch box 64. The plug 63 can be detached at any time to provide for the removal of the support 56 with a the lamp. i Ordinarily, one light will be used for each'ovencompartment. A door oporatedswitchitif) isprovided in the lamp-circuit. This switch is operated by a lever 66 attached to a rod 67 turning with the dOO1..' 1

The switch box 64 is ,.detachably. secured to the side. of the oven, for example, by screws, not shown. An auxiliary support for hold.- ing the switch. box whilethescrews orfbolts are put in place isprovided atv the top ofthe oven, as shown in Fig. ,6. This Support comprises aplate 68, which is secured tothe Oven at the top. The plate is secured tothe oven at its'bottom edge andhas; its upper. portion spaced awayfromthe side ofthe ovenwhereby a downturned edge 69cm the switch box may be hooked over the plate 68 to secure the box. e f 1 A ventilating flue 7 0 (Fig. 2) isprovided at the back endof each oven compartment. This flue opens into an upright pipe 71 and is controlled by a damper 72 which may be operated from the front of the oven by means of a rod 73 (Fig. 1) connected thereto. Suitable connections 74 are provided for admitting steam into the oven compartment for certain baking operations.

Thermometers 75 and 7 6 are provided for the upper and lower oven compartments respectively. Thesethermometers may be of any suitable construction and may, for example, comprise a thermostatic temperature responsive member which is located in the interior of the oven and communicates through the wall with visual indicating means on the exterior. As shown in Fig. 3, the temperature responsive element is placed in a conical recess 77 in the inner side of the oven wall. It will be observed that the temperature responsive element terminates substantially within the conical recess and consequently does not project into the baking compartment proper. This recess is formed in the inner metallic lining of the oven, as shown, by providing a suitable aperture in the lining and securing therein a cone-shaped metallic member 78. This construction allows the maximum circulation of the air in the interior of the oven around the thermostat so that the thermometer accurately registers the temperature, together with'the minimum reduction of thermal efiiciency. It will be observed that the cone-shaped opening allows more of the heat insulation to'remain due to the gradually tapered walls of the recess than would be possible if a cylindrical recess were used.

While I have describedmy invention as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto since various modifications thereof will suggest themselves to those killed in the art without departing from the spirit of my invention the scope of which is set forth in'the annexedclaims;

What I claim as new and desire to secure by. Letters Patent of the United States, is:

,1; An electric oven comprising walls forming a heating chamber provided with a door opening, supporting members adjacent the top of said chamber, an electric heating-unit slidably supported on said members, and pivotal supporting means for said members on which said members are movable to effect the removal of said heating unit through said door opening.

2. The combination with an electric oven provided with a door opening, of means for supporting an electric heating unit in said oven comprising bars forming supports secured to said walls at opposite sides adjacent the top of said oven, means for pivotally supporting said bars at the rear end of said oven, and'rneans for releasably supporting said bars at the front end of said oven so that said bars may be lowered to allow said heating unit to be removed through said door opening. 3. An electric oven comprising walls forming av heating chamber provided with a door opening of substantially the same width as said chamber, supporting members adjacent the top of said chamber extending from the front to the rear and pivotally mounted in the rear end of said chamber, an electric heating unit slidably mounted on said members,

and means for releasably securing said members at the front of said chamber whereby said members may be released at the front and lowered on their pivots to permit said heating unit to be removed through said door opening.

4.. An electric oven comprising walls forming an oven chamber provided with a door opening at one end of substantially the same width as said chamber but of reduced height, said opening being situated substantially midway of the height of said chamber, electric heating units in the top and bottom of said chamber and means for supporting said heating units so that they are rendered freely removable through, said door opening, the means for supporting the top unit comprising bars pivotally secured at one end to said walls.

5. An electric oven comprising walls forming a heating chamber provided with a door opening of lesser height than said chamber but of substantially the same width, said opening being spaced substantially equal distances fromthe top and bottom of said chain ber, rails at the top and bottom of said heat ing chamber on each side thereof, and heating units embracing substantially the entire area of'said heating chamber slidably mounted on said rails so as to be freely removable through said door. opening, said. upper rails being pivoted at the rear end of said chamber so that they may be lowered on their pivots to provide for the removal of said heating unit.

6. An oven comprising an inner metallic lining forming a heating chamber and provided with a throat opening at one end, an outer metallic lining provided with a door opening, a sealed connection between said throat and said outer lining at said door open- 1ng whereby said inner lining is supported, a support for the rear end of said inner lining comprising a metallic member having narrow contact areas with said inner lining, and heat insulating material between said linings.

7. An oven comprising an inner metallic lining forming a heating chamber and provided with a throat opening at one end, an outer metallic lining provided with a door opening, a connection between said throat and said outer lining at said door opening whereby said inner lining is supported at the outer end, and a support for the rear end of said inner lining including a metallic framework having small areas of contact with said inner lining whereby loss of heat by conduction is prevented, and heat insailating material between said linings.

8. An electric oven comprising walls forming a heating chamber provided with a door opening and a. relatively small aperture, an internal flange in said aperture, a curved transparent lamp guard closing said aperture seated on said flange to form therewith a steam-tight joint, said lamp guard being arranged to extend. into the interior of the oven, and a lamp extending through said aperture into said guard removable from the exterior of said oven.

9. An electric oven comprising walls forming a heating chamber, a side wall of said heating chamber being provided with a relatively small aperture, a transparent lamp guard closing the inner end of said aperture with a steam-tight joint, a removable base member secured at the outer end of said aperture, and a lamp in said aperture, secured to said base member.

10. An electric oven comprising walls forming a heating chamber, a side wall of said heating chamber being provided with a cylindrical aperture, a transparent lamp guard closing the inner end of said aperture with a steanrtight joint, a removable perforated base member secured at the outer end of said aperture, and a lamp in said aperture secured to said base.

11. An electric oven comprising inner and outer walls forming a heating chamber provided with a door opening and a relatively small aperture, said inner lining being provided with a threaded bore in said opening terminating with an internal flange, a transparent lamp guard provided with threads fitting in said bore, a gasket on said flange against which said guard is seated to form a steam-tight joint, an electric lamp in said aperture removable from the exterior of said oven.

12. An electric oven comprising inner and outer walls forming a heating chamber provided with a door opening and a relatively small aperture, said inner lining being provided with a threaded bore in said opening terminating with an internal flange, an electric lamp in said aperture extending into said oven, a transparent guard in said even fitting over said lamp and provided with a threaded rim fitting in said bore, a gasket on said flange against which said guard is seated to form a steam-tight joint, and a support for said lamp secured to the exterior of said oven.

In witness whereof, I have hereunto set my hand this 9th day of April, 1927.

JACOB L. SHROYER. 

